Calcutta, Aug. 14: A confidential report prepared by the Bengal pollution control board does not mention anything alarming about the colas now at the centre of a pesticide residue controversy.

The board’s tests on around five samples are said to have found pesticide contamination “marginally above” the draft permissible limit, but nowhere close to an NGO’s claim of the Calcutta cola count being “51.7 times” above the permissible limit.

The report was submitted to the state environment ministry in the wake of the storm over private test reports made public by the Delhi-based Centre for Science and Environment. According to the CSE, Calcutta topped the cola contamination list of 18 cities.

“I have received a report (on the contamination) but it is for internal consumption,” environment minister Mohanta Chatterjee told The Telegraph.“We do not have legal sanction to publish these results,” he added.

But environment activists said there is no legal bar on the board making the results public.

Pollution control board sources confirmed that the results of tests carried out on both Coca-Cola and Pepsi products had been found to be similar to the 2003 findings of the pesticide count above the prescribed limit, but not alarmingly so.

Chief minister Buddhadeb Bhattacharjee had said yesterday the Centre should take the final decision whether to ban the soft drinks or not. The state government is awaiting results from two more labs.

Responding to the PCB findings, Chandra Bhusan of CSE said: “Pesticide contamination levels can vary with change of batch, production process and input materials. Besides, during the monsoon, the pesticide concentration may be diluted in the groundwater. But Calcutta is definitely in the top bracket when it comes to average total pesticide contamination.”